Application of an automated light modulating material is expected in order to commonly realize energy saving and amenity in a portion such as a window glass in which great heat exchange occurs between an internal environment and an exterior environment of a room and a building such as a housing and a movable body such as a car (for example, Patent Document 1).
An “automated light modulating material” is enabled to control optical characteristics such as a transparent or reflecting state with a temperature. For example, when the automated light modulating material is applied to a window glass of a building, a solar light is reflected and heat is shielded by reflecting a solar light. Heat is absorbed by causing a solar light to transmit through the window glass.
One of the automated light modulating materials which are of most interest contains vanadium dioxide (VO2). The material uses thermochromic characteristics in which optical characteristics are reversibly changed by a temperature and which occurs when a phase transition occurs between a semiconductor phase of vanadium dioxide (VO2) and a metallic phase. The light modulating characteristics of an ambient temperature depending type are obtainable with this.
A glass containing the automated light modulating material may be obtained by a sputtering process of vanadium dioxide (VO2) to, for example, a glass substrate. After sputtering a thin film of vanadium dioxide (VO2) on a substrate, the thin film is transferred to a film, and the thin film transferred to the film is transferred to a final glass substrate. Then, a glass containing an automated light modulating material is obtainable (For example, Patent Documents 2 and 3).
However, under a forming method of an automated light modulating material using a sputtering process, it is necessary to heat a substrate so as to be a temperature of 400° C. Therefore, there is a problem that a manufacturing process is complicated and a cost increases. Further, there is a problem that application of a sputtering process to the window glass to an existing building is difficult.
As another method, the microparticles and dispersion liquid containing vanadium dioxide (VO2) are prepared, and installed in a member to which an automatic light-modulating property is given via a binding material. With this, manufacturing of the member having an automatic light-modulating property is considered (for example, Patent Documents 4-6).